The field of the invention pertains to devices for driving piles, sign posts and well pipes vertically into the ground.
Most devices for such purposes are large powered devices mounted on large trucks or cranes for portability. These devices require two or more operators and considerable set-up time. Large powered devices are much too expensive and unwieldy for ordinary metal sign posts, shallow wells and metal fence posts. Rather, the latter are usually driven manually with a sledge hammer or a tripod rig and weight.
With a view toward providing a simple inexpensive light duty powered device for driving sign posts, fence posts and shallow wells, applicant has developed the device disclosed below.
The new sign post driver comprises a piston which rests upon a post to be driven and a weighted cylinder which reciprocates vertically to impact the piston on the downstroke. The cylinder is raised for each stroke pneumatically and falls by gravity with or without an optional spring assist in the preferred embodiment. Optionally, combustion gas, mechanical or hydraulic power could be employed to raise the cylinder. The new sign post driver employs pneumatic control valves for manual or semi-automatic operation. The reciprocating cylinder is substantially smooth externally, making it less likely to snag an operator or other adjacent workers since workers may be close to the moving cylinder when driving sign posts in particular.